Skip to main content
. Author manuscript; available in PMC: 2021 Mar 6.
Published in final edited form as: Crit Rev Biochem Mol Biol. 2021 Jan 18;56(1):109–124. doi: 10.1080/10409238.2020.1869175

Figure 2.

Figure 2.

Polymerase usage during normal and stressed conditions. (A) Polymerase usage differs during replication initiation, elongation and termination. The first Okazaki fragments on both strands initiate leading strand synthesis. Their overlap means that Pol δ synthesize the short stretches of DNA on both strands at replication initiation sites. Pol ε and Pol δ follows the canonical division of labor for the majority of DNA replication. During termination, leading strand replication switches from Pol ε to Pol δ for the last a few Kbps. (B) Polymerase usage after homologous recombination-dependent replication restart. In S. pombe, when the replication fork is forced to stall at the RTS1 site and restart following RTS1 removal, the restarted replication predominantly uses Pol δ for synthesis of both strands. (C) Polymerase using during break-induced replication (BIR). The 3’ end of a single-ended DSB can invade the homologous sequence on the donor chromosome. DNA synthesis is forced to copy the rest of the donor chromosome. In contrast to normal DNA replication, the nascent first strand serves as the template for the second strand synthesis. Both strands are predominantly synthesized by Pol δ.